The present invention relates to railway hopper cars and, in particular, to an improved center sill construction therefor.
In a conventional railway freight car construction a center sill extends from one end of the car to the other and is located approximately in alignment with the coupling line. It serves primarily to transmit the longitudinal draft loads through the car and to aid in supporting the vertical loads between major cross members. The center sill is usually hat-shaped in transverse cross section and may be fabricated by welding two Z-sections together. In hopper cars it is necessary to install inverted V-shaped hoods on top of the hat-shaped center sill to allow lading to pass around the sill and out the bottom opening to unload the car and to prevent lading from accumulating on top of the center sill. This conventional type of hopper car construction is disclosed, for example, in U.S. Pat. No. 3,868,913.
In order to avoid the use of such a hood, hopper cars have been provided with tubular center sills which pass through the hoppers, the center sill being shaped and positioned so that lading will pass around it, thereby obviating a separate hood. Such a tubular center sill is disclosed, for example, in U.S. Pat. No. 4,003,319.
However, such tubular center sills have certain disadvantages. First of all, the conventional arrangement of a hat-shaped center sill cooperates with the associated hood to provide a convenient passage and support for the brake rod of the railway car. This passage and support is lost in the tubular center sill construction, which does not utilize an associated hood. Furthermore, both the tubular center sill and the more conventional hat-shaped center sill require the use of separate parts that extend out and below both sides of the center sill to form a lip for the hopper doors to seal against.